Torque converter



March 28, 1961 Filed Feb. 12, 195'? @YQ i 9.'

H. STANSFIELD ETAL TORQUE CONVERTER 2 Sheets-Sheet 1 March 28, 1961 H. sTANsFn-:LD ErAL 2,976,973

TORQUE CONVERTER Filed Feb. 12, 1957 2 Sheets-Sheet 2 INVENTORS. IgM/5 By JW@ Q6 "roRoUE'CoNvERIER Hamill Stansleld and llames Edge, Allentown, Pa., as`

signoi's to Carney-Stansteld Co'., a corporation of Pennsylvania 1 v y -The present invention relatesgenerally to a hydraulic transmission for changing speed and' converting torque and is useful, as for andthelike.

'It -is a general object ofthe present inventiony to provide a transmission characterized by means for automatically'declutching the driving and driven members thereof atk idle speeds, means foreffecting driving relation therebetween` smoothly and gradually as the speed of the driving member increases, and means for effecting a direct lock between the driving'anddriven members at high speeds to provide 'a Vdirect driving coupling therebetween. Itis a morezdetailed object of this invention to provide a transmission in which a piston type'fluid pump is em-y ployed housed in a 'transmission casing which is coupled for rotation with the driven member and for relative rotation with respect to the driving member, the fluid pump acting to circulatefluid within` a closed fluid path within the casing incident to such relative rotation.

1 It is -astill further object toprovide means for restricting the circulation ,of fluid within the transmission casing so that torque is developed to turn the transmissionpcasing and-driven member upon the achievement of a particular relation between the speed' of the driving member and the load imposed on the driven member.'` Y n s It is another `object to provide means for adjusting the restriction of circulation of fluid 4within the transmission example, in vehicles, Vmachine tools,

-Unid States Patent f casing, to vary the output power and torque charactenis` Y tics' of the transmission. l. L y y, n

'Y The objects of the invention thus generally set forth together ,with other objects andancillary advantagesyare obtainedby. the construction and arrangemeiit'shOWn by way of illustration ink the accompanying` drawingslin which: n

'Figure 1 is a perspective view with a r`portion cut away of a -fluid transmission embodying one illustrative formy of the present invention;

Fig. 2 is a cross-sectional viewrtaken substantially in the plane of lineslZ-Zof Fig. l;

`CFig. 3 is a crossfsectional view taken in,` v-oisetjA planes" shown as lines 3,-3 ofFig. 2;:

l Fig.f4 isa cross-sectional viewvof a 'fluid transmission f embodying a modified forni ofl the'pre'sent inve1'1tion'; rFig. 5 is a cross-sectional View taken plane 'oflines 5`5 of Fig. 4; f Fig. 6 'isa fragmentary, sectional view taken substan# tiallyin the planey of lines 6-/6 of Pig. 4. I

' While the' invention is` susceptible of various' modioaf tions and alternative constructions, thereis-shown in vthe' drawings and'will be herein; described in detail two' illustrative embodiments. It l,is to be understood, however,

thatvi-t is not hereby intended to k'limit thev inventionI to the Vspecific vforms disclosed., `In fact, it'fi's intended to cover all modifications, alternative constructions and equivalents falling within the spirit andscop'eof theinvention as expressed in the claims."x f

f `Referring more particularly tothe drawings, tlfieffo'rm is vembo'diecl'inla hydraulic transmission having a driving4 shaft 10, a `driven shaft'k 11vand means for coupling the driving shaft and' drivensharft together.,

yIn the'present instance, the coupling means includes a rotatable'transmissioncasing 12 connected to the driven shaft 11 for rotation therewith. 'The drive shaft is rotat-v ably journaled centrally in the transmission casing 12, and

-i s mounted for rotationrelative to the casing. l f Inj-accordance' witlizone aspect of the present invention, n as` illustrated,inV Figi ,1,there is provided a piston type erate,areinterconnectedthrough a porting arrangement so "as'to provide'f'or continuous ow of iluid confined in said "cylinders "andf'c'irculationl within the transmission casing nupon reciprocation of the pistons. fIn the present instance`(-li`igs.`1%3`),the communication between the cylinders, form-ing a closed fluid path within the transmission casing, is provided by passages inl each of the pistons and annular relief grooves in the region of and adjacent the 1tiarre'l camfZi); AOne Vsuitable porting arrangement is Vshownin iFig.Y 1,Y where each piston 15, 16 'is drilled at both rendsto provide passages therein, 23, 24 and 25, 26 respectively. The vertical opposed surfaces of the barrel cam 20 are also bothmachined to form annular relief grooves 27, 28 communicating with the passagesuin the pistons. lUpg'ni'reciprocatic'ni ofthe pistons, the pistons forceV 'or pump uid confined-within the cylindens,to and frorri thelannularjelief grooves 27, 28 adjacent' the barrel OamZOandQbetWeenthe cylinders. v ",In, the construction' and arrangement illustrated, the transmission casing'IZ-is formed integral with the driven' shaft' T11, which isA mounted in axial alignment with the driving'shaft 1l). The transmission casing 12 is formed of cylinderbarrls 30,231I connected in a fixed spaced relation bysmveansof'a ringf33, shown in Fig.V 2 in lapped "relation with the'foppositefacing internal surfaces- 'I o'f'th' cylinder'barrelfmmbersf30, 311. 'A headA 'plate 35 substantially the 'of the invention theref-shownforpurpioses f'illust'rtio'n f cient i toV 'preventL leakage fastened'to-the outer surface of the nbarrel memberv 30 on tl1`e`fdri\'fing"- shaftr'endvlof the transmission casing serves tolclosetlie casing and seal thefcylinders. To accommodate thedniving'shaft 10,"the'ltran'smission casing 1-2 is y boned centrallythrogh' the head plate`35, barrels 30, 31

and barrel camZtL? and 'the driving shaft is journaled therein supported-for rotationpby' bearings'37, 38 pressed misplace in recesses-39, '4 0, formed inthe internal facing "sujrfa'eiV ffth'ei'barrelfniemberjs 3031.*v 3;" 5:Y vv innig: theipisfonsls, lessa-cylinder 13, V 121- Iaretherem" shown in,Y a"` balanced arrangement.' Thee linders 3;;14arffolrmedby'pairsfofopposed=cylin der :baresi 41, l`42 :and-143; 44,"ciici1mferftia11ydispqsen y. raiialiy equnaisahtfromf die; axis efj the gransmission casing 112? in the cylinder' barrels 30, 31,' IEach, pair of piston 'are utilized, and the pistons areaccordinglydou#V vble "acting, inthe 'surfa'ceS of Y- the: pistonsr'andwcorresponding bore' Isufaces'being machinedsmoothtova clearance sutil` fluid 7between:the piston and h'GCYlinder boreswall'. 'l' As 'stated hereinbefo'r 'causare-p vid Y Y... it. -vw 1,. Jv catingthe fpistonsinithef cylinders incident to relative ro v Patented Mar. 2,8, 19,61,

ff V- 3 tation between the driving shaft and the transmission casing 12. lIn the illustrative form of the invention depicted in Figs. 1-3, said means includes a cam track 45,

on the peripheral surface of the barrel cam arranged pins 46, 47 are inserted in the center of the surface of the segmental cutout portions 48, 49, removed from the piston 15, 16. With this arrangement the peripheral surface of the barrel cam 20 rides against the surface 50, 51 of the cutout portions in the respective pistons, as shown in Fig. 3. The length of the segmental cutout portions 48, 49 need only be sufficient to permit the full stroke travel of the pistons during their reciprocation, and must be deep enough to permit the nesting of the pistons around the barrel cam without causing them to bind thereto and to interfere with the action of the pistons. Bushings 52, 53 mounted on the ends of the follower pins 46, 47

and riding in the cam track 45 formed on the peripheral surface of the barrel cam 20, are rotatable to reduce the friction between the pins and the cam track and increase the eniciency of the assembly;

The hydraulic transmission shown in Figs. 1-3, thus comprises driving and driven shafts 10, 11 respectively, connected by means of a unit including a plurality of pistons disposed in circumferentially `arranged cylinders in a transmission casing. Means are also provided forming a closed fluid path within the transmission casing, and also providing communication between the respective cylinders within the casing.

In Athe operation of this transmission, the transmission casing 12 is lled with a suitable uid such as transmission oil, which then is contained in the cylinders 13, 14 and in the annular relief grooves 27, 28. Upon rotation of the drive'shaft 10, and relative rotation between the driveshaft and the transmission casing 12, the pistons 1S, 16 disposed in each of the cylinders are caused to reciprocate land oil is transferred between the cylinders and circulated within the transmission casing. As the speed of the driving shaft 10 increases, and the rate of reciprocation of the pistons increases, the volume of uid circulated within the transmission casing, through the passages 23, 24 and 25, 26 in the ends of the pistons and in the annular relief grooves or space adjacent the barrel cam, correspondingly increases. A point is soon reached upon increase inthe speed of the driving shaft, where by reason of the restriction to Huid flow offered by the passages through the ends of the pistons,torque is developed tending to rotate the transmission casing with the driveshaft.

With no load on the driven shaft, the transmission casing remains lstationary u ntil the rate of rotation of the driving shaft with respect thereto is sufficient to overcome the resistance to rotation of the transmission body and driven shaft.- Uponthe rachievement of a predetermined differential in relativespeed between the drivingshaft and the transmissionpcasing, the transmission casingV thus begips to turn. This differential is Vestablished by factors Aincluding the diameter of the-passages in the ends of the 'pistons, ,the width Yof the relief grooves adjacent the barrel cam and the interior surfaces `ofthe barrel members, the viscosityv of the uid employed, Aand the amount of friction1 involvedfin vthe movement ofthe various. parts of the assembly. V f Y f With load applied tothe` driven shaft, a similaraction a, reached, the transmission casing and driven shaft remain stationary. When a predetermined differential in speed is achieved the driven shaft coupled to the load begins to turn with the driving shaft, the transition between rest and movement of the driven shaft being gradual and uniform due to the inherent nature of the fluid coupling between the driving and driven members.

In Figs. 4-6, a further illustrative form of the invention is shown. As in the previous instance, the transmission there shown includes a driving shaft 100, a driven shaft 1&1, coupled by means including a transmission casing 102. In this illustrative form, the transmission casing 102 is made in two parts or cylinder barrels, 103, 104 respectively, one part or barrel 103 having a central bore in which the driving shaft 100 is journaled, and the second part or barrel 104 being bolted to a iianged end plate 105 mounted on the driven shaft 101. Each of the parts or barrels 103, 104 is drilled with a plurality of circumferentially spaced, axially disposed cylinder bores 106, 107,V and 108, 109, the cylinder bores in each part of the transmission casing being axially aligned so as to form cylinders 110, 111 to` receive pistons 112, 113, each pair of viding communication between the cylinders.

takes place. ,'Initially, rotationof the driving shaft causes relative rotation between the driving shaft-.andthe transmission casing and the transmission casing and driven shaft remain at ,a standstill. I Uponl furthergincrease ,in speed of 'the driving shaft and untilra predetermined diierential vis aligned bores 106, 108 and 107, 109 receiving a single piston. An even number of these cylinder pairs are` disposed in circumferentially spaced relationship around the driving shaft 100. This disposition of the pistons and cylinders results in opposing forces of equal magnitude on diametrically opposite pistons, so that theaxial forces are balanced, thereby eliminating axial thrust on the shaft.

Each of said pistons 112, 113 is double acting and is mounted for reciprocation in the transmission casing 102 incident to rotation of the driveshaft ll relative to the casing.

In the present instance, the driveshaft 100 carries a barrel cam 114 having a cam track 115 disposed on the peripheral surface thereof. Each of the pistons 112, 113 is provided with a follower pin 1=16, 117 respectively, mounted in the piston by means of bearings 118 and provided with a tapered end portion 119 for riding in the groove in the barrel cam. The follower pins 116, 117 operate as cam followers, the end portions thereof being tapered so that the peripheral speed varies as the diameter increases, and matches the surface speed of the side walls ofthe camvgroove formed in the surface of the barrel cam. The provision of a tapered surface on the end portions of the pins 116-,117 and a similar tapered cross-section for the groove in the peripheral surface of the barrel cam, producing a match between theV surface speed of the barrel cam and the surface speed of thecam follower, reduces wear and provides a more elcient assembly.

Within the transmission casing 102, a closed uid path between the cylinder bores is provided by passages pro- In the present instance, each of the two parts or barrels 103, 104 making up the transmission casing 102 are provided with annular cavities 120, 121 of limited axial and radial eX- tent, surrounding the driveshaft *100. In each of the cavities 120,121 there is disposed a slidable plug'122, 123 respectively, each .having an annular Ygroove 124,` '1125, extending completely around the peripheral surface thereof. Communication between` the cylinders, 110, Y111 is provided by a series of radial passages 126 communieating with the cylinders and, in the position of the parts of the assembly shown in Fig. 4, with the4 annular grooves in the peripheral surface of each of the plugs 122, 123. The rpassages and grooves form with the cylinders a closed uid path through which uid contained in the cylinders, may be circulated upon reciprocation of the pistons incident to` relative rotation between the driving shaft 1100 andthe transmission casing '102. i f

.l In .the arrangement and construction illustrated ,in Figs.

showninFig 4, the plugs 122, 123are shiftable axially 1 more spaced essere@ tudinal bore extending therethrough. Within -thebore 1 27 5 is a plunger or control rod 128 having intermediatethe ends thereof a portion 129 of 'reduced diameter, and formed at each end with a tapered vsection '130,131 of gradually reduced crossfsection; Contiguous to the'portion-129 of reduced vdiameter of"the' p1u'nger'128, and the end portions 130, 1 31 thereof, the walls o f thehollow shaft 1 00 are slottel132, to'accommodateballs '133.-

Thegends-of the plugs 122, 123'which face outwardly, are champered or bevelled 134,"135 alongthe inner surface thereof, to bear` against the balls 133 r resting in the slots 132 and are adaptedv to cooperateftherewith such that uponoutward'moyement of the balls,fthe plugsv 122=, 123 vare caused to' slidel inwardly-toward'the centralpart of the transmission casing, againstfthe action Aof springs 13 6 vbiasing the plugs outwardly along the shaft.

In the construction and arrangement shown in Figs. 4-6, means are provided for adjusting therestriction of communication betweenY the cylinders "the trans'i' mission casing itself. As shown, this means includesa plungeror control. rod, slidably mounted in the centralA longitudinal bore within the hollow driveshaft 100. :This control member or'r plunger, is reciproeable-axially of the hollow shaft100 by means ofa thrust ring 137, supported about the driveshaft 100` for relative" movement.; The inner surface Vthlere'ofis also tapered focoactign with'balls 133 contained within slots 132jin the wallof the hollow driveshaft 100, 's'ch 'thatfaxialliiovement of'- they thrustning 137 resultsV inf corresponding axial movel nient of the control rodor plunger 'containedfwithinthe' drive'sh'aft. Each'of the arrayof balls may` comprise asymmetrical arrangementof a plurality of ballsftwo'or equidistantly about thefdr'iveshaft desired. f

AThus byeXternal ac ti on`," either through manually op,-l

erated er automatically-operated meansithecontro'l rod l123 moved in correspondence:the 'rewith. Such movement of the thrust 'ring, control rod, andjballs, 'results [in movement of ythe plugs toffremove troniregistration'thev annlar'grooves inthe' plugs andthe radialA passages corn-v niunicating between the annular grooves and the 'c'ylindersg' Upon gradual movement of theA thrust ringfandjcontrol rod, theYV annular grooves ea'c'h are graduallyrmovedontf of registration with them'outhsof th'ejradialV passages, and the extent of communication' between the'feylinders isigradually'reduced, vuntil apoint Ais'reached whe vth annular grooves andradial passages arecompletelygo ofA registration, :when communication ybetween' 'the 'cylirifl A' de'rsis ncompletely interrupted. ff

To "operate the transmission shown in' Fig transmission casing, asin the-Vc'ase'of the illufstr e bodiment 'of thefinvention previously;describedjinfc seccion with Pigs.- L1 2isglir st Yf11ed2wirh a; suitblen j ir'as ltra' nsx'nissiofn oil." Withv no'load on the'l shaft101,'nd`t he'driving shaft lllqrotatingatl pee'dI; thj pistons 112,` 113 are causedltc reciprocate nrtheitA respective' 'cylinders' 110,v 11,1 'farmed in the trnsmissio casing 102,'"andin the position of the parts the assembly as shown in l"ig.V 4, oil`i`si.c ircul" ed'threugh" the passagesl 126'annula`r grooves- 124,"125' the plugs 122,123, between thefcylinder'swandflin'fa 'closed' Huid" path formed within the transmission casing;f"'I'he"`pi Sto1'1fs are'bo'red 'at each end140, toincrease .the,fvolume' fkv vuidlyvhich 'mayjbe contained withinthe'fcylindersfad jacent'th'e'ends ofthe pistons, This `also produces better y coolin'gfdue to fthe inceasedfvolume offluid'eontainedi?` Withingwthetransrnission easing, andtcooling isfurther improyelby providing tins 141 on ythe fout'sideperip h/reralE walls of the transmissioncasingfl02 lltrnay be net :esf: serrer adris'ablsi eineapprenons@ mandenme;

f ciprocate:andcirculate'uid in4 a-'closed fluid path the friction generated within thefapparatus,

cooling means in connection withthe'transmisson, now# ever;v inl'most applications the specic features illustrated provide for adequate cooling, and smooth ecient operation of `the transmission. 'y Y v."In order to increase the eliiciency of the unit, the hollowdn'veshalft 100 centrally journaled the transmission casing 102, may be supported in bearings 142,i 143 pressed into place within .recesses formed in the interior `of the parts 103, 1,04, making up the trans-- mission casing. Leakage of transmission lluid from the transmission casing may be prevented by an O-ring 1414 surroundingthe driveshaft 100, and seated in annular plug-145 which is machined to lit closely yabout the drivesha'ftand threaded into place in the drive shaft end ofV thel casing. 'v f Y .The plug 145 when in placejfo'rms a stop to locate the control `rod assembly with the yperipheral annular grooves in the members 122, 123 in registration with the radial passages 1-26- which communicate with the cylindeis.` At' the other end of the transmission casing, a plug 146is provided .threaded ingplace within the casing having a recess 147 provided to clear the end of the driveshaft 100. A The plug 146 forms a stop to limit the extent ofA axial movement ofthe controlrod assembly in a direction toremove the annular grooves from registration withthe radial passages in thel casing. The plugs 145zand.146thus also provide means for adjusting the control rod assemblyrfor optimum performance, by permitting adjustment of -the extent of axial movement permitted of this assemblyinfthe casing. -r

..1 To .prevent axial movement of the driveshaft 100'withinrthe transmission casing,-thrust\washers 148,149 areprovidedencircling-,the driveshaft and adjacent the ends ofthe barrel cam4 114, serving as spacers torpositionthe 4barrel cam intermediately' of the transmission casing. Thus,the thrust washers bear against the barrel cam and 'l alsovagainstI the innerk race of bearings 1142, 143, supcam A114, ,asin theinstance off'the invention illustrated infEigs'. lf3, segmental portionsare removed intermediate thends of the pistons tofproviderecessed surfaces 153.-' r 'Ihefifollower pins 116, 117' are inserted into the pistons in the A.center .of thetsurface` 'of the lsegmental cutout porti.01;zs. vWith this ,arrangement the peripheralsurface of' theabarrel camy 114 rides closely against the surface of the-,cutout portion of .the'respective pistonsas shown in=Fig.;6. The amount of materiallongitudinally re moved from .the piston need only be sufficient to permit tliefullistrokegitravel of. the pistons yduringv their reciproc ati r n 1, ,a n'd must4 be` deep yenoughiwto vpermit thenesting f of thepistons around `the-'barrel cam without causing tained the transmission-casing: are caused to -rethei,tran smissioncasing. .As the speed'ofv the driving shaft--increases, however, vthe vcommunication between s thecylinders being: restricted, even with'theplugs 122,- 123 positioned as Shown, torque fis developed -to causeY thegtransmissioncasing and.;driv`en.'member to turn in stepr with; the; driving member. The differentialin speed betweenthe members and thus the 'speed of the fdriving member at rlwhicl1` `the idrivenrnember and transmission casing'begin rotation, depends'upon a number'of factors includingtheextent of restriction between the cylinders,

cosity ofthe "uid employed.-

tobindoninterfere withthe action thereofj f f, Asaherein'beforle .described= the. transmission system of Eigs.. A operat'es so that upon lowl speed' of the driving shaft 100, and relative rotation Vlb'etweensaidy driving`r shaft and the transmission vcasingllll, the pistons con# force acting on theuid vcontained within the transmis- Sion. easing. This-would be experiencedwith both forms of the invention illustrated. f As thespeed of rotation of the transmission increases, centrifugal force causes the fluid contained within the transmission casing to become more diicult tomove in a direction angularly'disposed to the direction of centrifugal force. speeds of rotation the resistance to piston movement increasesv and as the transmission casing turns in step with the driving shaftthe differential in speed between the transmission casing and the driving shaft is gradually reduced. Upon reaching the minimum speed at which this effect is realized, they transmission casing and driven shaft can be considered to be locked in step with the driving shaft and turning at a speed determined by the operating characteristics of the unit. The action due to centrifugal lforce produces a gradual reduction toward zero of, the, diiferential of speed between the. driving andrdriven members` as thespeed of the driving shaft t and thus the transmission casing and` drivenshaft) Vincreases, and a gradual increase toward'unity off-the speed ratio between the members.

To obtain `a direct drive between. the driving shaft and transmission casing in the' arrangement of Figs. 4 6, communication between Vthe cylinderswithin-the transmission casing may bel completely interrupted by means of the thrust ring and plunger assembly. .Complete interruption of communication results in trapping the uid within the cylinders and prevents reciprocation of. thepistons. The rotary motion ofthe driveshaft,V therefore, is trans. mitted directly through the locked pistons tothe transmission casing and hencey tothe driven shaft..V By shift-l ing the thrust ring toward the right in Fig.V 4,. suicientA to causesuch .interruptiomvthe driving and driven shaftsv maybe directly coupled together. v

By shifting the thrust ring only partially, the

restriction Thus, at high rupted passages in either direction to and from the chambersso that said pistons are restrained against movement upon rotation of the driveshaft by the restricted circulation of lfluid between said chambers developing torque to turn thedniven shaft. l i, I Y i l 2. Inga hydraulicvtransmission,the combination cornprising a, rotatable casing, a driveshaft rotatably journaled centrally inA said casing, a driven shaft coupled to said casing for rotation therewith, a plurality of pairs vof aligned cylinders arranged in said casing inrcircurriferen'-v tiallyspaced relation about said driveshaft and having chambers adjacent the endsthereof, double acting pistons reciprocably mounted in eachz of said pairs of cylinders, each piston having an end portion slidable within the respective cylinder and; acting on fluid in the respective chamber, a b arrel cam'mounted on said driveshaft intermediate the ends of said cylinders, means connecting said barrel-eam'to said. pistons for reciprocating said pistons incident to rotation'of said barrelrcarrr-,relative to the casing, means adjacent each end of the barrel cam defining a restricted annular passage radially inward of the cylinders and surrounding the driveshaft, and means dening uninterrupted passages of small cross section connecting the chambersk at the ends of each cylinder with the adjacent annular passage providing for flow through said uninterrupted passages in either direction ,to and to`v communication maybe increased and the drivenv shaft cause-d to `tui-nat a smaller differential in speed relative` to the dxiveshaft, producing a speed ratio approaching unity depending upon ,the extentof communication;

The thrust ring may be operatedmanually,v or auto# inatically `by means responsive to vehicle speed, for exi' ample, where the transmission .of thissinvention is'employedto drive a vehicle. The rtriction Vto communi# cation may be varied bysuch means so that at idling speeds of the vehicle engine the driving and driven shafts are veffectively declutched, at intermediate speeds the driving shaft turns the rdriven shaft with a differential in speed varying in accordance withe the vehicle speed; while at high speeds thedriving and driven shaftsjmay be coupled inv a direct drive. relation. for obtaining 4maxi-l mum fefficiency inVv gas consumption andi minimumslip:4 -In eachof-the foregoing illustrations ofl theinventior'i,`

aparticular form andarrangement of'par-tsis' shown and`` l illustrated'.l It isV not, to be construed,V however; thatl thel inventionr is .to` be limited'. thereto, but it is intended to embrace all alternative constructions within the spirit andscopeotthe appended claims. 1 v We claim as our; invention: Y f

l. In ya` hydraulic-gtransmission; theicom-bination com#vv prising a'rotatable, outer.` casing, -a drivesha-ft rotatablyJv journaledtin said. casing, a. driven' shaft non-rotatably* fixed onsaid casing,.a plurality of `pairs of-aligned-cylin ders arranged in said :casingin circumferentiallysp'aced* relation aboutsaiddriveshaft. andl having chambers. ad jacent the 'ends thereof;;double. actinglpistonsreciproeablyY mountedeineachapair of cylinders yandra'cting onfluidin said chambers, means;forz reciprocating. said pistons-imei cident to Y relative;V rotation between 1 said.V casing and saidi driveshaft, means-at eachgend-ofthe `casing-.defining aereii stricted'` annular,l passage radiallyf.. inv/ard'A of the: cylinders f and;sairrcimdingV thedriveshaft; and: means.y defining uninterrupted passages of smallcrosssection connecting the'-`= chambers `-at v the-.ends ,of 1 each cylinder with fthe adjacent annular*passageproviding'for1 owqthroughwsaid uninterJ I5-i andi'actinfgen uid-"intthei respecti'veichambers'," means;

- prising a rotatable V,outeracasing,-y a hollow driveshaft-rofrom the chambersso. that said pistons are restrained against movement .upon rotation ofthe dri-veshaft byA the restricted circulation of fluid between Ysaid chambers developjngtorqueto turnthe driven shaft.

Y 3. In a hydraulic transmission, the combination comprising arOtatable outer casing, a hollow, driveshaft rotatably journaled ,insaid.V casing, means for couplingpa drivenI shaft to said casing for rotation therewith, a plurality'v ofA cylinders arranged insaid. casingV in1 circumferentially lspacedrelation about said driveshaft and having Vchambers yadjacent the ends thereof, doubleactingl pistons` reciprocablyv mounted ineach of said cylinders and `acting onfluid in said'chambers, lmeans. for reciprocating said pistons incidentv torot'ationof saiddriveshaft relative to the casing, said casing having an annular portion inward of the cylindersV surrounding. the driveshaft at eachend of'thecasingand definingabore therebetween, means.V

connecting the cylinder chambers With the ybore-at the same end ofl the casing including anrluninterruptedpassage of small-.cross section in said` casing connecting' each chamber withV aV `port in the WallY of. said bore, a valve sleeve ysli'dably receivedin eachbore and having a peripheral groovedening a restricted annular passage fac-v v ing said wall` andv registeringY with` the ports in said wall toA provide forV owin either .direction` throughthe ,un-v

interruptedpassages to andfrom the cylinder chambersso `that 'upon rotation of the. driveshaft said pistons are restrained`v against movement bythe restrictedfcirculation,

O f, fluid between,therchamljers'` developing torque to turn the, drivenshaft, andf-meansfor adjusting the ow between saidlchamberstorcontroLthe torque applied to turn the dive'nfshaftincludingt alcontiol-rovd slidably mounted in` the. hollow` diveslafh. saidY shaft-v havingradial openingsY adjacentfsgaidbore'srespectively, `camrnfingportions carriedby said(V controlrod .adjacent said openings, operating' members ,extending through said openings1andA bearing againstfsaid'sleye valvesysaid operating members `co,-

acting` ,withf .saidffcarnming l portions .such that movement ofj the Acontrolfrod is translatedfyinto movement ofthe said groveandsaid ports;

f 4 Aa Hydraulic transmission, tlie combinationgcom- 5^ sleeve' vvalves to the extent of.- registration between pistonsi'eciprocably mounted' inieach' of said' cylinders" the ends thereefgwdoubler acting for reciprocating said pistons incident to rotation of said driveshaft relative to the casing, means providing restricted communication between said cylinders and forming a fluid path within said casing including an annular portion at each end of said casing surrounding said driveshaft and dening a bore therebetween, means connecting the cylinder chambers with the bore at the same end of the casing including an uninterrupted passage of small cross section in said casing connect-ing each chamber with a port in the wall of said bore, a valve sleeve slidably received in each bore having a peripheral groove facing said Wall defining a restricted annular passage radially inward of the cylinders and registering with the ports therein to provide for llow in either direction through the passages to and from the cylinder chambers so that upon rotation of the driveshaft said pistons are restrained against movement by the restricted circulationof uid between the chambers developing torque to turn the driven shaft, and means for adjusting the flow between said chambers to control the torque applied to turn the driven shaft including a control rod slidably mounted in the hollow driveshaft, and means actuated by said control rod for moving said valve sleeves to vary the extent of registration between said peripheral groove and said ports.

5. In a hydraulic transmission, the combination comprising a rotatable outer casing, a driveshaft rotatably journaled in said casing, a driven shaft non-rotatably fixed on said casing, a plurality of pairs of alined cylinders arranged in said casing in circumferentially spaced relation about said driveshaft and having chambers adjacent the ends thereof, double acting pistons reciprocably mounted in each pair of cylinders and acting on fluid in said chambers, a bar-rel cam mounted on said driveshaft axially between the alined cylinders for reciprocating said pistons incident to relative rotation between said casing and said driveshaft, means at each end of the casing axially adjacent the barrel cam defining a restricted annular passage radially adjacent the inner edges of the cylinders, and means including an uninterrupted passage of small cross section extending axially through each end 40 of each of said pistons connecting the cylinder chambers 10 providing for flow in either direction to and from the cylinder chambers so that said pistons are restrained against movement upon rotation of the driveshaft by the restricted circulation of yHuid between said chambers developing torque to turn the driven shaft.

6. In a hydraulic transmission, the combination comprising a rotatable outer casing, a driveshaft rotatably journaled in said casing, a driven shaft non-rotatably xed on said casing, a plurality of pairs of aligned cylinders arranged in said casing in circumferentially spaced relation about said driveshaft and having chambers adjacent the ends thereof, double acting pistons reciprocably mounted in each pair of cylinders and acting on iluid in said chambers, means for reciprocating said pistons incident to relative rotation between said casing and said driveshaft, means at each end of the casing defining a restricted annular passage radially inward of the cylinders and surrounding the driveshaft, means delning uninterrupted passages of small cross sectionr connecting the chambers at the ends of each cylinder with the adjacent annular passage providing for flow through said uninterrupted passages in either direction to and from the chambers so that said pistons are restrained against movement upon rotation of the driveshaft by the restricted circulation of fluid between said chambers developing torque to 4turn the drive shaft, and means for adjusting the iiow through said passages between said chambers to control the torque applied to turn the driven shaft.

References Cited in the iile of this patent UNITED STATES PATENTS 970,640 McClintock Sept. 20, 1910 1,787,246 Greening et al Dec. 30, 1930 1,924,508 McCarthy Aug. 29, 1933 2,215,103 Holpfer Sept. 17, 1940 2,370,640 Deardori et al. Mar. 6, 1945 2,497,993 James Feb. 2l, 1950 2,667,952 Ainsworth Feb. 2, 1954 2,723,739 Maier Nov. 15, 1955 FOREIGN PATENTS 285,452 Italy May 12, 1931 

